903
FNUS71 KBOX 130004
FWSBOX

Spot Forecast for Sterling Fair...MEMA
National Weather Service Boston/Norton MA
804 PM EDT Sat Sep 12 2026

Forecast is based on forecast start time of 0600 EDT on September 13.
If conditions become unrepresentative, contact the National
Weather Service.

.DISCUSSION...

Showers with periods of heavy downpours are expected starting
after 8/9 AM tomorrow, with the highest chances for the periods of
heavy rain peaking around 11 AM/noon. This should clear out more
towards the evening hours, generally after 5 PM. With regards to
totals, currently expecting around 2" over the course of the late
morning through the evening hours. Any highly localized higher
totals cannot be entirely ruled out, though. A few thunderstorms
are possible, particularly in the afternoon.

.SUNDAY...

Sky/weather.........Cloudy. Showers and isolated thunderstorms
                    through the day.
Chance of pcpn......100 percent.
Chance of rain......99 percent.
Chance of thunder...23 percent.
Begin/end of pcpn...
Max temperature.....Around 72.
Min humidity........93 percent.
Surface winds (mph).Light winds in the morning becoming southeast
                    around 5 mph, then shifting to the east early
                    in the afternoon becoming light.
Rainfall amount.....0.84 inches.
Pcpn amount.........0.84 inches.
Mixing height.......1000 ft AGL.
Transport winds.....South 7 to 9 mph shifting to the east around 9
                    mph early in the afternoon, then shifting to
                    the southeast late in the afternoon shifting to
                    the northeast 8 to 10 mph late in the
                    afternoon.
Smoke dispersal.....Poor (3000 knot-ft).
LVORI...............8.
ADI.................1 to 12.

TIME (EDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........87  80  91  88  100 94  92  92  95  87  94  94
Weather cov.....SCH CHC LKY DEF DEF DEF DEF LKY CHC CHC SCH
Weather type....RW  RW  RW  RW  RW  RW  RW  RW  RW  RW  RW
Tstm cov........ISO ISO ISO ISO ISO ISO ISO         ISO ISO
Chc of pcpn (%).20  30  70  80  100 90  80  60  50  40  20  10
Chc of rain (%).20  50  60  90  90  100 100 100 100 60  50  30
Chc of thdr (%).10  10  20  20  20  20  20  20  20  20  20  10
Temp............61  61  63  64  66  67  68  68  70  70  70  71
RH..............93  97  97  100 100 100 100 100 97  97  100 97
Surface wnd dir.S   S   S   S   SE  SE  E   E   E   E   NE  NE
Surface wnd spd.2   2   3   3   3   5   5   5   5   3   3   3
Surface wnd gst.7   8   8   9   10  10  10  10  10  8   7   6
Mix hgt (kft)...0.4 0.5 0.5 0.8 0.8 0.9 1.0 1.0 0.9 0.8 0.9 0.9
Transp wind dir.S   SW  S   SW  S   S   S   SE  E   SE  NE  N
Transp wind spd.8   8   8   8   7   8   9   9   9   9   10  8
LVORI...........6   6   6   8   8   10  10  10  10  8   7   6
ADI.............9   9   9   9   8   1   1   1   1   11  12  9
Vrate kt-ft/1K..3   3   4   5   5   7   8   8   7   7   8   6
Ventrate Cat....PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR

.SUNDAY NIGHT...

Sky/weather.........Mostly cloudy. Slight chance of showers early
                    in the morning.
Chance of pcpn......20 percent.
Chance of rain......29 percent.
Chance of thunder...9 percent.
Begin/end of pcpn...
Min temperature.....Around 60.
Max humidity........100 percent.
Surface winds (mph).Light winds becoming west 5 to 6 mph early in
                    the morning.
Rainfall amount.....0.08 inches.
Pcpn amount.........0.08 inches.
Mixing height.......400 ft AGL.
Transport winds.....North around 8 mph shifting to the east around
                    7 mph early in the evening, then shifting to
                    the north early shifting to the west 6 to 10
                    mph in the late evening and early morning
                    shifting to the northwest around 12 mph.
Smoke dispersal.....Poor (2200 knot-ft).
LVORI...............8.
ADI.................3 to 9.

TIME (EDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........79  75  67  70  66  64  53  54  55  73  83  88
Weather cov.....                                    SCH SCH SCH
Weather type....                                    RW  RW  RW
Tstm cov........
Chc of pcpn (%).10  0   0   0   0   0   0   0   10  20  20  20
Chc of rain (%).30  30  30  10  10  10  10  10  10  20  20  20
Chc of thdr (%).10  0   0   0   0   0   0   0   10  10  10  10
Temp............70  70  68  66  66  66  65  65  65  65  63  62
RH..............97  97  97  100 100 97  100 97  97  93  97  97
Surface wnd dir.N   NW  W   SW  W   W   W   W   W   W   W   W
Surface wnd spd.2   1   1   2   2   3   3   3   5   5   6   6
Surface wnd gst.5   3   3   5   6   7   8   9   10  12  13  14
Mix hgt (kft)...0.7 0.5 0.4 0.4 0.4 0.5 0.5 0.5 0.5 0.4 0.4 0.5
Transp wind dir.N   E   N   SW  W   W   W   W   W   W   NW  NW
Transp wind spd.8   7   7   6   7   8   8   9   10  10  12  12
LVORI...........6   9   8   10  9   8   9   8   7   6   6   6
ADI.............9   3   3   3   3   4   4   4   7   7   8   8
Vrate kt-ft/1K..5   3   2   2   3   3   3   4   4   4   4   5
Ventrate Cat....PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR  PR

$$
Forecaster...BRW
Requested by...D Leavitt
Type of request...OTHER
.TAG 2621738.0/BOX
.DELDT 09/12/26
.FormatterVersion 2.0.0
.EMAIL daniel.leavitt@mass.gov